Optical Remote Sensing To Quantify Fugitive Particulate Mass Emissions from Stationary Short-Term and Mobile Continuous Sources: Part I. Method and Examples

Abstract

The emissions of particulate matter (PM) from anthropogenic sources raise public concern. A new method is described here that was developed to complete in situ rapid response measurements of PM mass emissions from fugitive dust sources by use of optical remote sensing (ORS) and an anemometer. The ORS system consists of one ground-based micropulse light detection and ranging (MPL) device that was mounted on a positioner, two open path-Fourier transform infrared (OP-FTIR) spectrometers, and two open path-laser transmissometers (OP-LT). An algorithm was formulated to compute PM light extinction profiles along each of the plume's cross sections that were determined with the MPL. Size-specific PM mass emission factors were then calculated by integrating the light extinction profiles with particle mass extinction efficiencies (determined with the OP-FTIRs/OP-LTs) and the wind's speed and direction. This method also quantifies the spatial and temporal variability of the plume's PM mass concentrations across each of the plume's cross sections. Example results from three field studies are also described to demonstrate how this new method is used to determine mass emission factors as well as characterize the dust plumes' horizontal and vertical dimensions and temporal variability of the PM's mass concentration.

Fugitive Particulate Matter Emissions to the Atmosphere from Tracked and Wheeled Vehicles in a Desert Region by Hybrid-Optical Remote Sensing

“…The photon counts were corrected, normalized and then converted to normalized relative backscatter (NRB) values (Campbell et al, 2002). To convert the 2-D NRB profiles to 2-D light extinction profiles the near-end LIDAR inversion technique was used (Fernald et al, 1972;Du et al, 2011a) with a reflective target that was located so that the plume was between the MPL and the target. The MPL recorded photon counts at 1 Hz for the entire duration of each plume.…”

“…NEI estimates are based on PM mass emission factors (EFs) in U.S. EPA's AP-42 database and are rated as highly uncertain (U.S. EPA, 2015a). The high uncertainty reflects the nature of fugitive emission plumes that can: 1) have short lifetimes (often less than one minute) (McFarland et al, 2007;Du et al, 2013), 2) exist with large spatial scales (tens to hundreds of meters) (Du et al, 2011a), 3) can travel aloft, and 4) be heterogeneous (McFarland et al, 2007). There remains a need for improving the accuracy of fugitive PM EFs (Du et al, 2011a) with measurement methods appropriate for the characteristics of fugitive PM plumes to improve national and global PM emission inventories.…”

“…This paper describes a new hybrid-ORS method and its results from field implementation to measure fugitive PM EFs for PM 10 and PM 2.5 for tracked and wheeled military vehicles traveling on unpaved roads in a desert region. The difference between the ORS method reported in Du et al (2011a) and this hybrid-ORS method is in the way the MEE values for PM 10 and PM 2.5 are determined. In the earlier ORS method, MEE values were determined by first determining particle size distributions (PSDs) using wavelength-dependent light extinction measurements obtained with an open path-laser transmissometer (OP-LT) and an open-path Fourier Transform Infrared spectrometer.…”

“…In the earlier ORS method, MEE values were determined by first determining particle size distributions (PSDs) using wavelength-dependent light extinction measurements obtained with an open path-laser transmissometer (OP-LT) and an open-path Fourier Transform Infrared spectrometer. Then, MEE values were calculated using PSDs and assumed particle density and refractive index using Mie-Lorenz theory (Varma et al, 2006;Du et al, 2011a). In the hybrid-ORS method reported here, MEE values are determined by simultaneously measuring real-time light extinction with an OP-LT and PM 10 and PM 2.5 mass concentrations with optically based DustTrak™ monitors.…”

Open burning and open detonation PM10 mass emission factor measurements with optical remote sensing

“…The hybrid-ORS method is appropriate for determining OB/OD EFs because it enables to scan numerous cross-sections of the PM plume as it disperses. Thus, detection of the plume occurs in real time, in situ, and with no need for numerous point measurement devices (Du et al, 2011a). For the hybrid-ORS method, mass PM concentration measurements from a tapered element oscillating microbalance (TEOM) and optical measurements from a micropulse light detection and ranging (LIDAR; MPL) device were used to determine the PM EFs during a 2010 field campaign at the Tooele Army Depot in Utah.…”